Localized f Electron Aspect in Heavy-Fermion Intermetallic YbRh₂Si₂

We point out that there is more and more experiments showing the almost perfect localization of thirteen f-electrons in the canonical heavy-fermion system: YbRh₂Si₂. The revealing of the Yb³⁺ crystal-field (CEF) states confirms the Quantum Atomistic Solid State Theory. QUASST was the only theory, which has claimed from 1992 the existence of the discrete CEF electronic structure and the Kramers doublet ground state in heavy-fermion intermetallics. The removal of the on-site Kramers degeneracy via spin-dependent interactions is origin of the large specific heat at low temperatures (a hallmark of the heavy-fermion phenomena) and of low-energy neutral spin-like excitations. The Kondo resonance is related to the slight splitting of the Kramers doublet ground state of the Yb³⁺ ion.